dask.dataframe.Index.align

dask.dataframe.Index.align¶

Index.align(other, join='outer', axis=None, fill_value=None)¶

Align two objects on their axes with the specified join method.

This docstring was copied from pandas.core.series.Series.align.

Some inconsistencies with the Dask version may exist.

Join method is specified for each axis Index.

Parameters

otherDataFrame or Series

join{‘outer’, ‘inner’, ‘left’, ‘right’}, default ‘outer’

axisallowed axis of the other object, default None

Align on index (0), columns (1), or both (None).

levelint or level name, default None (Not supported in Dask)

Broadcast across a level, matching Index values on the passed MultiIndex level.

copybool, default True (Not supported in Dask)

Always returns new objects. If copy=False and no reindexing is required then original objects are returned.

fill_valuescalar, default np.NaN

Value to use for missing values. Defaults to NaN, but can be any “compatible” value.

method{‘backfill’, ‘bfill’, ‘pad’, ‘ffill’, None}, default None (Not supported in Dask)

Method to use for filling holes in reindexed Series:

pad / ffill: propagate last valid observation forward to next valid.
backfill / bfill: use NEXT valid observation to fill gap.

limitint, default None (Not supported in Dask)

If method is specified, this is the maximum number of consecutive NaN values to forward/backward fill. In other words, if there is a gap with more than this number of consecutive NaNs, it will only be partially filled. If method is not specified, this is the maximum number of entries along the entire axis where NaNs will be filled. Must be greater than 0 if not None.

fill_axis{0 or ‘index’}, default 0 (Not supported in Dask)

Filling axis, method and limit.

broadcast_axis{0 or ‘index’}, default None (Not supported in Dask)

Broadcast values along this axis, if aligning two objects of different dimensions.

Returns

tuple of (Series, type of other): Aligned objects.

Examples

>>> df = pd.DataFrame(  
...     [[1, 2, 3, 4], [6, 7, 8, 9]], columns=["D", "B", "E", "A"], index=[1, 2]
... )
>>> other = pd.DataFrame(  
...     [[10, 20, 30, 40], [60, 70, 80, 90], [600, 700, 800, 900]],
...     columns=["A", "B", "C", "D"],
...     index=[2, 3, 4],
... )
>>> df  
   D  B  E  A
1  1  2  3  4
2  6  7  8  9
>>> other  
    A    B    C    D
2   10   20   30   40
3   60   70   80   90
4  600  700  800  900

Align on columns:

>>> left, right = df.align(other, join="outer", axis=1)  
>>> left  
   A  B   C  D  E
1  4  2 NaN  1  3
2  9  7 NaN  6  8
>>> right  
    A    B    C    D   E
2   10   20   30   40 NaN
3   60   70   80   90 NaN
4  600  700  800  900 NaN

We can also align on the index:

>>> left, right = df.align(other, join="outer", axis=0)  
>>> left  
    D    B    E    A
1  1.0  2.0  3.0  4.0
2  6.0  7.0  8.0  9.0
3  NaN  NaN  NaN  NaN
4  NaN  NaN  NaN  NaN
>>> right  
    A      B      C      D
1    NaN    NaN    NaN    NaN
2   10.0   20.0   30.0   40.0
3   60.0   70.0   80.0   90.0
4  600.0  700.0  800.0  900.0

Finally, the default axis=None will align on both index and columns:

>>> left, right = df.align(other, join="outer", axis=None)  
>>> left  
     A    B   C    D    E
1  4.0  2.0 NaN  1.0  3.0
2  9.0  7.0 NaN  6.0  8.0
3  NaN  NaN NaN  NaN  NaN
4  NaN  NaN NaN  NaN  NaN
>>> right  
       A      B      C      D   E
1    NaN    NaN    NaN    NaN NaN
2   10.0   20.0   30.0   40.0 NaN
3   60.0   70.0   80.0   90.0 NaN
4  600.0  700.0  800.0  900.0 NaN

dask.dataframe.Index.add

dask.dataframe.Index.all